Effects of exercise modality on insulin resistance and functional limitation in older adults: a randomized controlled trial.
ABSTRACT Authorities advocate that resistance and aerobic exercise are essential for reducing risk factors for chronic disease and disability in older adults. However, the incremental effects of combined resistance and aerobic exercise compared with either modality alone on risk factors for disease and disability is generally unknown.
Participants were 136 sedentary, abdominally obese older men and women recruited from September 30, 2002, through November 15, 2006, at Queen's University. Participants were randomized to 1 of the following 4 groups for 6 months: resistance exercise, aerobic exercise, resistance and aerobic exercise (combined exercise), or nonexercise control. Primary outcomes were analyzed by an intent-to-treat model and included changes in insulin resistance by hyperinsulinemic-euglycemic clamp and functional limitation using the average change in 4 tests combined (average z score).
After controlling for age, sex, and baseline value, insulin resistance improved compared with controls in the aerobic exercise and the combined exercise groups but not in the resistance exercise group. Improvement (mean [SE]) in the combined exercise group was greater than in the resistance exercise group (9.2 [1.3] vs 1.8 [1.3] mg/mL/microIU per kilogram of skeletal muscle per minute x100 [P < .001]) but not in the aerobic exercise group (9.2 [1.3] vs 6.5 [1.3] mg/mL/microIU per kilogram of skeletal muscle per minute x100 [P = .46]). Functional limitation improved significantly in all groups compared with the control group. Improvement in the combined exercise group was greater than in the aerobic exercise group (0.5 [0.1] vs -0.0 [0.1]; standard units, z score [P = .003]) but not in the resistance exercise group. Improvement in the resistance exercise group was not different from the aerobic exercise group.
The combination of resistance and aerobic exercise was the optimal exercise strategy for simultaneous reduction in insulin resistance and functional limitation in previously sedentary, abdominally obese older adults.
clinicaltrials.gov Identifier: NCT00520858.
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ABSTRACT: The association between waist circumference (WC) and mortality is particularly strong and direct when adjusted for body mass index (BMI). One conceivable explanation for this association is that WC adjusted for BMI is a better predictor of the presumably most harmful intra-abdominal fat mass (IAFM) than WC alone. We studied the prediction of abdominal subcutaneous fat mass (ASFM) and IAFM by WC alone and by addition of BMI as an explanatory factor. WC, BMI and magnetic resonance imaging data from 742 men and women who participated in clinical studies in Canada and Finland were pooled. Total adjusted squared multiple correlation coefficients (R(2)) of ASFM and IAFM were calculated from multiple linear regression models with WC and BMI as explanatory variables. Mean BMI and WC of the participants in the pooled sample were 30 kg/m(2) and 102 cm, respectively. WC explained 29% of the variance in ASFM and 51% of the variance in IAFM. Addition of BMI to WC added 28% to the variance explained in ASFM, but only 1% to the variance explained in IAFM. Results in subgroups stratified by study center, sex, age, obesity level and type 2 diabetes status were not systematically different. The prediction of IAFM by WC is not improved by addition of BMI.PLoS ONE 01/2012; 7(2):e32213. · 4.09 Impact Factor
Article: Exercise for the treatment and management of overweight women with polycystic ovary syndrome: a review of the literature.[show abstract] [hide abstract]
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Article: Importance of characteristics and modalities of physical activity and exercise in the management of cardiovascular health in individuals with cardiovascular risk factors: recommendations from the EACPR (Part II).[show abstract] [hide abstract]
ABSTRACT: In a previous paper, as the first of a series of three on the importance of characteristics and modalities of physical activity (PA) and exercise in the management of cardiovascular health within the general population, we concluded that, in the population at large, PA and aerobic exercise capacity clearly are inversely associated with increased cardiovascular disease risk and all-cause and cardiovascular mortality and that a dose-response curve on cardiovascular outcome has been demonstrated in most studies. More and more evidence is accumulated that engaging in regular PA and exercise interventions are essential components for reducing the severity of cardiovascular risk factors, such as obesity and abdominal fat, high BP, metabolic risk factors, and systemic inflammation. However, it is less clear whether and which type of PA and exercise intervention (aerobic exercise, dynamic resistive exercise, or both) or characteristic of exercise (frequency, intensity, time or duration, and volume) would yield more benefit for each separate risk factor. The present paper, therefore, will review and make recommendations for PA and exercise training in the management of cardiovascular health in individuals with cardiovascular risk factors. The guidance offered in this series of papers is aimed at medical doctors, health practitioners, kinesiologists, physiotherapists and exercise physiologists, politicians, public health policy makers, and individual members of the public. Based on previous and the current literature overviews, recommendations from the European Association on Cardiovascular Prevention and Rehabilitation are formulated regarding type, volume, and intensity of PA and regarding appropriate risk evaluation during exercise in individuals with cardiovascular risk factors.European journal of preventive cardiology. 05/2012;